1. Field of the Invention
The present invention relates to a device for reading/writing information of a tool with a data carrier used in a machine tool, and in particular, relates to a device for reading/writing information of the data carrier of the tool held by an automatic tool changer of the machine tool, and the machine tool having the device.
2. Description of the Related Art
A read/write device of tool information is used to read/write tool information (or tool data) stored in a data carrier provided to a tool contained in an automatic tool changer of a machine tool. The tool information includes a tool number, a tool diameter, a tool length and a life counter, etc. After the tool is contained in the automatic tool changer, the tool information read by the read/write device is automatically transmitted to and stored in an NC device. By virtue of this, man-hour can be reduced and input errors can be prevented, in comparison to manual data input.
In order to read/write tool data in the automatic tool changer, it is necessary to precisely position a read/write head of the tool information read/write device relative to the data carrier of the tool. This is because a distance between the data carrier and the read/write head and an allowable range of the deviation between center positions thereof are limited, in order to stably communicate between the read/write head and an IC chip used as the data carrier, etc.
As relevant prior art documents, JP H06-005076 Y discloses a read/write device of tool information used in a tool magazine device in which a pot containing a tool is driven by a chain. This document describes that: a member, which contacts a V-groove of the tool and limits a positional deviation the tool in the axial direction thereof, is positioned in an opening of an arm into which the circumference of the V-groove of the tool is inserted; a key, having a guide surface for limiting a positional deviation in the rotational direction of the tool, is fitted with a drive key groove of the opening of the arm; and a data carrier of the tool can be correctly positioned relative to the read/write head due to the member and the key.
Further, JP H06-000632 U discloses a tool information reader used in a chain-driven automatic tool changer. Concretely, this document describes that: a first base arranged on a bracket fixed to the tool changer so that the first base is movable in a first direction parallel to an axis of a tool holder; a second base and a drive unit are arranged on the first base so that the second base is moved by the drive unit in a second direction perpendicular to the axis of the tool holder; a third base is arranged on the second base so that the third base is movable in a third direction perpendicular to both the first and second directions; a pair of guide sections are arranged on the third base so that the pair of guide sections fit with radial ends of the tool holder when the guide sections are moved in the second direction; and a reading head is arranged between the pair of guide sections. This document also describes that the reading head can be correctly positioned on a predetermined position of the tool holder, even when a stop position of the tool holder of the tool changer has dispersion.
In the tool information read/write device (or reader) used in the chain-driven tool changer as described above, the position of the data carrier of the tool and the position of the read/write head may be deviated from each other, due to the influence of gap between a chain and a sprocket wheel. In order to solve this problem, in JP H06-005076 Y, the arm having the read/write head is held at a neutral position by a spring, and the circumference of the V-groove for gripping of the tool is used as a guide section for adjusting the positional relationship between the data carrier of the tool and the read/write head. However, when a tool changer, such as a turret, utilizing the V-groove of the tool, is used, the read-write device may interfere with a tool holding structure of the turret. Therefore, the read/write device as disclosed in JP H06-005076 Y cannot be used in the turret-type automatic tool changer.
The turret can rotate about a rotation axis thereof and also can swing about a swing axis due to an up-and-down motion of a spindle head. Therefore, even when the read/write device can be positioned without occurring interference, the read/write device cannot be correctly positioned relative to the position of the data carrier of the tool so that the read/write head can carry out read/write process.
In the prior art, since the read/write device can be applied to only a machine tool in which an automatic tool changer and a processing room are separated from each other, it is not necessary to consider that machining dust generated during the processing is adhered to the read/write head. However, since the turret-type automatic tool changer is usually positioned in the processing room, the machining dust generated during the processing may be adhered to the read/write head and the reading/writing of the data may be hindered.
On the other hand, the invention of JP H06-000632 U is intended to solve a problem due to slackening or elongation of the chain of the chain-type tool changer, and thus the above problem regarding the turret-type tool changer, not the chain-type tool changer, cannot be solved.